Bouncing Ball Physics help

I’ve created a game similar to Bounce by Ketchapp, but I am having difficulties and hoping someone could help me.
the ball does not maintain its jump height, after jumping from 1st to 2nd platform the jump height decreases.
second more important problem, the ball just flies away when hitting the edges, can i disable edge collision? so no forces but the player control can control the ball through the X axis. Same physics as in the game Bounce

Look into the physics material and remove any friction and set bouncing to 1. Actually, I once had a case when doing so may even get the ball to bounce higher. So you may have to tweak all that until you get the right values.

I am also currently making bounce game. I my game if have not used bouncy material instead i have used addForce in the OnCollisonEnter2D function of the ball

This would work perfectly

using UnityEngine;
using System.Collections;

public class BallScript : MonoBehaviour {

// Use this for initialization
float ball_xvel,ball_yvel;
bool mouseDown;
void Start () {
	ball_xvel = 0;
	ball_yvel = 8;

// Update is called once per frame
void Update () 
		if(gameObject.rigidbody2D.velocity.y > 8)
			gameObject.rigidbody2D.velocity = new Vector2(ball_xvel,ball_yvel);
void OnCollisionEnter2D(Collision2D col)
	Debug.Log ("collision");
	rigidbody2D.AddForce (new Vector2(0,1000));